Light emitting diodes (LEDs) are a type of light emitting components composes of semiconductor materials from elements of the III-V group. As LEDs generally have advantages such as long life, small size, high shock resistance, low heat generation and low power consumption, they have been widely used in household equipment and a variety of indicators or light sources. In recent years, a trend of development of LEDs has been towards multi-color and high brightness, and accordingly the application of LEDs has extended to the fields of large-scale outdoor billboards, traffic lights and related fields. In the future, LEDs may become a primary type of light source with energy saving and environmental friendly features, and thus may be widely used in various decorative or indicative lighting applications.
For example, LED package structure may be installed in buttons of an electronic device to enable the buttons to emit light. This feature facilitates operation of the buttons of the electronic device in the dark by a user or enhances the aesthetics of the electronic device due to the emitted light. In this example, the ability of the LED package structure to control the intensity of light emitted in each direction is important, especially in view of the need to efficiently transmit the light emitted by the LED package structure to provide good lighting capacity for the buttons.